Showing papers on "Transient (oscillation) published in 1980"
TL;DR: In this paper, the time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field are derived from Maxwell's equations.
Abstract: The time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field, are derived from Maxwell's equations. Depending on how the line voltage is defined, two formulations are possible. One of these formulations is considerably more convenient to apply than the other. The assumptions made in the derivation of the transmission-line equations and the boundary conditions at the terminations are discussed. For numerical calculations, the transmission -line equations are represented by finite-difference techniques, and numerical examples are included.
893 citations
01 Jan 1980
261 citations
01 May 1980
255 citations
02 Jun 1980
TL;DR: In this paper, the time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field are derived from Maxwell's equations.
Abstract: The time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field, are derived from Maxwell's equations. Depending on how the line voltage is defined, two formulations are possible. One of these formulations is considerably more convenient to apply than the other. The assumptions made in the derivation of the transmission-line equations and the boundary conditions at the terminations are discussed. For numerical calculations, the transmission -line equations are represented by finite-difference techniques, and numerical examples are included.
209 citations
TL;DR: In this article, two methods have been developed for analyzing MOS transients: analytical and quasi-static approximation, which is useful when the stray capacitance dominates MOS transient performance; and numericaf, which uses a new boundary value method which can be applied over a wide range of operating speeds.
Abstract: Two methods have been developed for analyzing MOS transients. One method is analytical and uses the quasi-static approximation. It is useful when the stray capacitance dominates MOS transient performance. The second method is numericaf and uses a new boundary value method which can be applied over a wide range of operating speeds. This method includes secondary effects and nonuniform doping. The validity and Iimits for both methods are verified by comparison with measurements. Transit-time delay and charge-pumping effects are also analyzed using the numerical method. Examples of short-channel behavior of MOS devices are included.
144 citations
TL;DR: In this paper, two methods have been developed for analyzing MOS transients: analytical and quasi-static approximation, and numerical and a new boundary value method which can be applied over a wide range of operating speeds.
Abstract: Two methods have been developed for analyzing MOS transients. One method is analytical and uses the quasi-static approximation. It is useful when the stray capacitance dominates MOS transient performance. The second method is numerical and uses a new boundary value method which can be applied over a wide range of operating speeds. This method includes secondary effects and nonuniform doping, The validity and limits for both methods are verified by comparison with measurements. Transit-time delay and charge-pumping effects are also analyzed using the numerical method. Examples of short-channel behavior of MOS devices are included.
125 citations
TL;DR: The chief practical distinction between transient and steady-state evoked potentials lies in the trade-off of speed versus information, which can be much speedier than recording transient evoked Potential, and can be accomplished for much lower signal levels even in adverse environments.
Abstract: Transient stimuli follow each other a t sufficiently long intervals that the visual system returns to its initial state before the next stimulus occurs. Steady-state stimuli are delivered at a greater rate, so that the response to one stimulus has not died away before the next stimulus is delivered. Transient stimulation gradually changes into steady-state stimulation over a range of stimulus repetition rates. The minimum stimulation rate for steady-state stimulation is the lowest rate for which appreciable overlap occurs between the response to one stimulus and the Occurrence of the next stimulus. This rate is different for different types of stimuli. For a linear system the transient response has a fixed relationship to the steady-state response. Consequently, transient and steady-state descriptions of a linear system’s behavior are equivalent, and can be regarded as alternative formulations of the same data. However, the visual and auditory pathways commonly show several types of nonlinear behavior. For example, when successive responses run into each other they may not summate even approximately linearly. In principle, therefore, transient and steady-state stimulation can produce responses that provide complementary information about the sensory system under test. However, this possibility has so far been little exploited. At the present time, the chief practical distinction between transient and steady-state evoked potentials lies in the trade-off of speed versus information. As discussed below, recording steady-state evoked potentials can be much speedier than recording transient evoked potentials, and can be accomplished for much lower signal levels even in adverse environments. For example, mains interference is usually no problem when recording steady-state evoked potentials, but care must be taken to minimize it when recording transient evoked potentials. The price that must be paid for these advantages is that, over a given recording time, steady-state evoked potentials provide less information than transient evoked potentials. As described below, steady-state evoked potentials can be quantified in a less arbitrary manner than transient evoked potentials. Steady-state evoked potentials can be split up into a small number of harmonic frequency components, each recorded by a separate Fourier analyzer. A Fourier analyzer’s output is equivalent to two numbers (namely, amplitude and phase), and these are quite unequivocal. In contrast, describing and measuring a transient evoked potential may not be straightforward, especially when the waveform is unusual or complex (FIGURE 2 illustrates one of the many problems). In such situations different experimenters may measure transient evoked potentials quite differently, may disagree as to whether an evoked potential is normal or abnormal, and may even disagree as to whether an evoked potential is
123 citations
TL;DR: In this paper, a measurement method for deep levels in semiconductors is proposed, by which the measurement of the transient change of capacitance is performed under an isothermal condition (Isothermal Capacitance Transient Spectroscopy).
Abstract: A new measurement method for deep levels in semiconductors is proposed, by which the measurement of the transient change of capacitance is performed under an isothermal condition (Isothermal Capacitance Transient Spectroscopy). The method allows us to construct a precise measurement and analysis system by a programmable calculator. Computer simulation and experiment by the method in the case of Au-doped Si are demonstrated. It is shown that the method is one of useful tools for spectroscopic analysis of deep levels in semiconductors.
114 citations
TL;DR: In this article, Popov's stability criterion has been generalized to one for systems with multi-argument non-linearities, and a Lur'e type Lyapunov function has been constructed in a systematic method.
Abstract: In this paper, techniques for analyzing transient stability of power systems with field flux decays via Lyapunov's direct method have been developed. First, Popov's stability criterion has been generalized to one for systems with multi-argument non-linearities, and a Lur'e type Lyapunov function has been constructed in a systematic method. Next, the transient stability region has been defined, and its variation has been investigated in detail. As a result, the second type of instability has been introduced. By a numerical example, stability characteristics of the power system have been illustrated, and the validity of the Lyapunov function has been proved.
84 citations
TL;DR: In this article, the authors calculated the transient responses of crystals to the application of a driving force for three growth mechanisms: disk-shaped clusters, spiral growth and two-dimensional nucleation.
84 citations
TL;DR: In this article, a deep-level transient spectrometer (DLTS) was built to measure current transients, rather than the usual capacitance transients in p-n junctions.
Abstract: A deep-level transient spectrometer (DLTS) has been built that measures current transients, rather than the usual capacitance transients, in p-n junctions. The system was developed to optimize sensitivity for the study of low-concentration processing-induced defects. An analysis of its performance as a function of timing parameters is presented. A noise analysis of both capacitance and current transient measurement is presented, showing that neither method has an inherent sensitivity advantage, and that both should be capable of detection limits of about 10-7to 10-8of the shallow doping concentration. Noise measurements indicate that a detection limit of 10-7times the doping has been obtained. Spectra of a processed p+-n diode with no intentional contamination show several defect levels in the 10-5N D , or 1010cm-3, range. Spectra of gold-doped p+-n diodes yield emission data in good agreement with accepted values.
TL;DR: In this paper, the solution to the transient subsonic motion of a nonuniformly moving screw dislocation starting from rest is obtained, where the screw is assumed to be fixed.
Abstract: The solution to the transient subsonic motion of a nonuniformly moving screw dislocation starting from rest is obtained.
TL;DR: In this paper, a unified approach for the static and transient dynamic linear and geometrically nonlinear analysis of Mindlin plates including initial imperfections is presented, where the effects of transverse shear deformation and rotatory inertia are automatically taken into account.
Abstract: A unified approach is presented for the static and transient dynamic linear and geometrically nonlinear analysis of Mindlin plates including initial imperfections. The effects of transverse shear deformation and rotatory inertia are automatically taken into account. A finite element idealization is adopted and the quadratic Lagrangian Mindlin plate element is used together with selective integration. Several numerical examples are presented and compared with results from other sources.
TL;DR: In this paper, the role of the finite, non-zero collision duration in high electric fields is examined for its effect on transient and overshoot response of the carrier velocity and energy.
Abstract: The role of the finite, non-zero collision duration in high electric fields is examined for its effect on transient and over-shoot response of the carrier velocity and energy. The finite collision duration introduces a temporal retardation effect on the collisional relaxation mechanisms for energy and momentum. As a consequence, the effective temperature also undergoes an overshoot behavior, which leads to a general quickening of the total transient response. Calculations were performed for steady, homogeneous fields utilizing a displaced Maxwellian approach. These calculations were performed for GaAs and Si and have significance for sub-micron devices in these materials. The generally faster response leads to the prospect of improved high frequency properties over what is normally expected.
TL;DR: In this paper, the problem of three-dimensional transient heat flow in the rotors of large turbine-generators is solved using a finite element formulation and employing new arch-shaped elements.
Abstract: The problem of three-dimensional, transient heat flow in the rotors of large turbine-generators is solved using a finite element formulation and employing new arch-shaped elements. Applications to negative sequence current heating and to rotor mechanical unbalance caused by thermal asymmetries are discussed. The method is shown to agree well with analytical calculations for heat flow in cylinders. Isothermal plots on a rotor isometric illustrate the pattern of heat flow.
TL;DR: In this paper, the authors used the two-fluid model of two-phase flow to calculate wave propagation speeds and stability limits for the illustrative case of a frictionless horizontal stratified gas-liquid flow, and the predicted stability limits were found consistent with available observations on the stability of the stratified flow regime.
TL;DR: In this paper, a model for determining the transient currents and voltages induced within long shielded coaxial cables by an impinging electromagnetic pulse (EMP) was presented for determining their internal voltages and currents.
Abstract: A model is presented for determining the transient currents and voltages induced within long shielded coaxial cables by an impinging electromagnetic pulse (EMP). The transmission-line theory is applied to establish the differential equations describing the behavior of the cables in the presence of a uniform plane traveling wave. At first, induced sheath currents are calculated taking into account different coupling modes. Then, internal voltages and currents are computed via the surface transfer impedance of cable shields for one and multilayer outer conductors. Comparison with measurements show the validity of the proposed method. The computer codes developed for this purpose have been found to be a very useful tool for the optimization of shielded transmission cables.
DOI•
01 Nov 1980TL;DR: In this article, a new electromagnetic transient formulation for multiconductor power transmission lines based on the z-transform was developed, where the basic relationships of propagation in the frequency domain were developed leading to recursive sequences for solution in the time domain.
Abstract: The paper develops a new electromagnetic transient formulation for multiconductor power transmission lines based on the z-transform. Beginning with the basic relationships of propagation in the frequency domain, the successive steps of z-transform analysis are developed leading to recursive sequences for solution in the time domain. The case of lossless propagation is considered initially in introducing z-transform analysis in its application to transmission-line electromagnetic transient evaluations, following which a general formulation is derived into which series-path line parameter frequency-dependence is directly reflected. Test analyses based on a z-transform model complemented by a simplified equivalent-source representation and applied to a 160 km, 400 kV untransposed single-circuit transmission line confirm the high inherent accuracy and low computing-time requirements of the method.
TL;DR: A method of prediction of transient behaviour is presented and applied to variable speed cutting on a lathe where such transients are significant and under certain conditions larger transient vibrations occur.
Abstract: Conventionally the stability analysis of machine tools is restricted to determining if a particular operation will become unstable. The transient behaviour is not examined in any further detail. However, under certain conditions larger transient vibrations occur even though the process may ultimately be stable. A method of prediction of transient behaviour is presented and applied to variable speed cutting on a lathe where such transients are significant.
TL;DR: In this paper, the authors demonstrate how shortcomings of this method can be avoided and higher flexibility can be achieved by separating the signal processing from the data acquisition by using a high-resolution capacitance measurement system with a resolution of 0.002 pF and 5 μs in time.
Abstract: The analysis of transient phenomena originating from relaxation processes is a tool for material and device characterization. The time constants of the transients provide information about the energy levels involved, and the transient amplitude is coupled to the density of occupied states. A convenient method for the analysis of exponential transients is the use of correlation‐spectroscopic techniques. An example is deep level transient spectroscopy, a capacitance method for the study of deep impurities in semiconductors. The correlation with a weighting function is in this case conventionally made by hardwired instruments. We demonstrate here how shortcomings of this method can be avoided and higher flexibility can be achieved by separating the signal processing from the data acquisition. The hardware is a high‐resolution capacitance measurement system with a resolution of 0.002 pF in capacitance and 5 μs in time. As a result of the measurement, which is considerably faster than analog methods, a data array describes the response of the sample with regard to time and temperature. Several signal processing routines are applied to the data to filter out specific information.
16 Jun 1980
TL;DR: This paper shows how to model switching regulators using the SPICE2 computer aided circuit analysis package for small signal ac, dc, and large signal transient simulations, both open and closed loop.
Abstract: The wide spread use of pulse width modulators in power supplies has created a need for computer models of the switching and control elements. This paper shows how to model switching regulators using the SPICE2 computer aided circuit analysis package for small signal ac, dc, and large signal transient simulations, both open and closed loop. With these models, a switching regulator design can be quickly and accurately evaluated at low cost.
TL;DR: In this article, the response of a turbine-generator unit's rotor system to an electrical system disturbance requires complex models of both the electric network and mechanical system, and significant parameters for both these models are discussed and illustrated using simplified transmission system models.
Abstract: The analysis of the response of a turbine-generator unit's rotor system to an electrical system disturbance requires complex models of both the electric network and mechanical system. The significant parameters for both these models are discussed and illustrated using simplified transmission system models. The effects of higher frequency electrical torque components are shown to be dominant factors in determining the stress on small components such as turbine blades while the lower frequency components provide the main stimulus to the main shaft sections.
TL;DR: In this article, the carrier is identified as C2H2 and a possible alternate assignment of the transient carrier to a geometrical isomer, such as H2C=C (vinylidene) radical is discussed.
Abstract: Absorption spectra of a long‐lived transient in the 140 and 157 nm region have been observed as the result of direct excitation of C2H2. The strongest features also are seen as the result of CH2CO photolysis. The carrier is identified as C2H2. A possible alternate assignment of the transient carrier to a geometrical isomer, such as H2C=C (vinylidene) radical is discussed.
01 Jan 1980
Patent•
08 Jul 1980
TL;DR: In this paper, the transient signal is detected as a function of time at least during the time intervals and is sampled, numbered and registered, temporally marked, and a processing operation is carried out which commences with a preprocessing in which an unprocessed numerical representation of the transient phenomenon as a functional representation of time is subjected to statistical evaluation of elements of the numerical registration which correspond temporally to the successive time intervals, followed by a smoothing digital filtering which provides a smoothed numerical representation.
Abstract: In a method of geophysical prospection a transmitter dipole and a receiver dipole which is sensitive to an electromagnetic field are positioned in cooperation with the subsoil. An impulsive excitation current is applied repeatedly to the transmitter dipole, the excitation current comprising a group of pulses of alternate polarity, each followed by zero current. The transient signal, which is produced thereby at the output of the receiver dipole, is repeatedly detected, and the transient signals are processed to obtain a figurative representation of the transient phenomenon which facilitates geophysical interpretation. Time intervals which are consecutive to excitation pulses and simultaneously with the excitation zero current are defined, these time intervals being of a predetermined duration, chosen to substantially cover all the useful parts of the transient phenomenon. The transient signal is detected as a function of time at least during the time intervals and is sampled, numbered and registered, temporally marked. A processing operation is carried out which commences with a preprocessing in which an unprocessed numerical representation of the transient phenomenon as a function of time is subjected to statistical evaluation of elements of the numerical registration which correspond temporally to the successive time intervals, followed by a smoothing digital filtering which provides a smoothed numerical representation of the transient phenomenon, cleared of a substantial part of the surrounding noise.
TL;DR: In this paper, two low capacity, LiBr, absorption chillers (4.5 and 25 kW) expressly designed for solar cooling have been tested and two alternative control strategies are suggested together with the appropriate plant schemes.
Abstract: Resume Two, low capacity, LiBr, absorption chillers (4.5 and 25 kW) expressly designed for solar cooling have been tested. The manufacturer's performance curves have been checked, then the investigation was extended to different values of the main parameters. Transient behaviour has been examined. For solar cooling duties it was found that control by simple on-off cycling is unacceptable owing to the large resulting energy loss. Two alternative control strategies are suggested together with the appropriate plant schemes.
30 Jun 1980